All codes listed below will affect and alter the experience of online play.
Capcom frown upon online cheating, and if you're caught you may be banned from playing online forever. ARC does not take ANY responsibility for penalties that may occur if these codes are used online. Use them at your own risk.

Resident Evil: Outbreak (PAL)

(M) (Datel)
W58U-DX0K-GGDH5
MRM4-EPNZ-B2698
19FH-TEM3-HMT77

Lone Wolf Mode (Jay007)
8W9X-2KQT-66DU7
D26D-Z02A-0P08G

Only Have 1 Ally (Be warned, this code may be saved) (Jay007)
URK9-4UWW-ACXUZ
1H81-HXTR-87D85

Player Is Invisible (Jay007)
P1WJ-NKDY-XMKX2
CCC5-E3JZ-M37NQ

AIPC 1 Is Invisible (Jay007)
JPV5-4ZWQ-NKJWP
Y4NP-78PP-26PGQ

Remove Virus Guage (L2) (Jay007)
BGTF-9HNY-NNQXQ
P95N-UTQY-WEX39
FVXA-128R-AVX10

Unlock File 1, File 2, and unused File NPC's (Jay007)
A8KQ-GYZZ-Y212V
CCB6-380U-CK07Z
WAEU-G71Z-KZDHX
MAEJ-9Z5Y-YVH2K
T3PN-89DP-HUPNG
7WTK-WM43-17M7W

Joker (Pyriel)
0A273DDC 0000XXXX

Item Slot 1 Modifier (Jay007)
00465894 000000XX

Item Slot 2 Modifier (Jay007)
00465895 000000XX

Item Slot 3 Modifier (Jay007)
00465896 000000XX

Item Slot 4 Modifier (Jay007)
00465897 000000XX

Special Slot Modifier (Jay007)
00465898 000000XX

Costume Modifier (Jay007)
004657D4 000000XX

NPC Character Modifier (Jay007)
004657CC 000000XX

Notes

Backup your save before using this code! Read here for more information.

FFFE - Select
FFFD - L3
FFFB - R3
FFF7 - Start
FFEF - Up
FFDF - Right
FFBF - Down
FF7F - Left
FEFF - L2
FDFF - R2
FBFF - L1
F7FF - R1
EFFF - Triangle
DFFF - O
BFFF - X
7FFF - Square

Requires Joker to use.

00 - Type A 
01 - Type B 
02 - Type C (Females Only)

You can choose the "type" of the NPC character you choose by selecting one of the main characters. The NPC character will have the "type" of whatever character you chose to play as. In other words, if you use the value for Mac, and pick Cindy as your character, Mac will have Cindy's "type", abilities, items, and voice.

This isnt all the values however, as there are atleast 90 playable characters we know of, not including the weird ones I'm finding now and again.

00 - Mac
01 - Mac
02 - Rodriguez
03 - Conrad
04 - Hunk:B
05 - Hunk
06 - Miguel
07 - (Face)
08 - U.S.S.1
09 - *
0A - Arnold
0B - Matt
0C - Billy
0D - Hursh
0E - Hursh (with an odd face problem)
0F - *
10 - *
11 - Peter
12 - Marvin
13 - Fred
14 - Andy
15 - *
16 - Jean
17 - Tonny
18 - (Injured Tonny)
19 - Keeper 1
1A - Keeper 2
1B - Austin
1C - Clint
1D - Bone
1E - Bob
1F - (Zombie Waiter)
20 - Nathan
21 - Samuel
22 - *
23 - Will
24 - (Zombie Will)
25 - Roger
26 - *
27 - Carter
28 - Greg
29 - Scholar 1
2A - Scholar 2
2B - Jake
2C - Gary
2D - Man 9
2E - *
2F - Micky
30 - Al
31 - Maskman
32 - Al B
33 - Ben
34 - (Little Girl)
35 - Regan
36 - Regan B
37 - Monica
38 - Rinda
39 - Rita
3A - *
3B - Mary
3C - Kate
3D - *
3E - *
3F - Danny
40 - Danny B
41 - Gill
42 - Gill B
43 - *
44 - *
45 - *
46 - (Bald Doctor with goatee)
47 - *
48 - *
49 - (Cindy)
4A - Doctor 4
4B - *
4C - *
4D - *
4E - *
4F - *
50 - *